Furnace Error Code 57: What It Means And How to Fix It

If you operate a home or commercial furnace, you will likely experience a problem sooner or later. A furnace error code is one of the most common indicators that something is amiss with your unit. A furnace error code can alert you to a specific problem and help you troubleshoot the issue. While all furnaces have different types of codes, most of them follow this standard format. Knowing what each code means and how to respond accordingly can prevent small problems from escalating. If your furnace has an error code or another problem, it may shut down until the problem is fixed. Before you turn on your system again, be sure to perform maintenance on it so it doesn’t happen again soon. The repair and maintenance procedure depends on the specific make and model of your boiler and its particular error codes. Here are some common issues and their corresponding alerts that go along with them as well as how to troubleshoot them:

Error Code 57: Blown Control Fuse

When a fuse blows in your furnace control, it will typically display error code 57. A blown fuse indicates that there is a short circuit in your furnace, which is often caused by a sticking limit switch or a broken wire. A short in the wiring can cause excessive heat and potentially start a fire. If a fuse has blown in your furnace’s wiring, an electrician should repair the issue as soon as possible to avoid a fire hazard and burnout.

Error Code 21: Blown Burner Or Bake Element

Error code 21 is an alert that one of your burners or bake elements has blown out. This could be caused by a faulty spark ignitor or a low gas pressure. If a flame ignitor is not sparking correctly, the gas flow to that burner may be blocked or faulty. If gas pressure is not at the correct level, the burner may not receive enough gas to ignite. Before you can fix the problem and continue using your furnace, you should first shut off the unit to avoid burning out the remaining elements. You can repair the faulty ignore or replace the faulty burner.

Error Code 24: Shorted Gas Supply Valve

If you see error code 24, the gas supply valve is likely shorted. You can check for an issue with the gas supply valve by switching the system off, removing the valve, and cleaning it out with a wire brush. If the valve is severely damaged, you may need to replace it. Before you do any repairs or replacements, you should turn off the unit and let everything cool down.

Error Code 42: Loaned Thermostat Or Electronic Controls

Error code 42 is a general alert that your thermostat or furnace controls are loaned. If a furnace has electronic controls, it may show an error code if they do not recognize a valid signal from the thermostat. If your thermostat is not communicating with the furnace, your system may not function as it should. If your thermostat is on loan, you should contact the company that loaned it to you so they can help you fix the problem.

Error Code 48: Problem With Combustion CH

If your furnace displays error code 48, the CH combustion is not working correctly. During the combustion process, the heat produced from the burners travels up to the furnace fan and then to the heat exchanger. The combustion CH is responsible for monitoring the amount of air entering the furnace to make sure it is the correct amount. If there is too little or too much air, the CH combustion may not function correctly. Fortunately, you can check the combustion CH and make adjustments if necessary.

Conclusion

If you operate a home or commercial furnace, you will likely experience a problem sooner or later. A furnace error code is one of the most common indicators that something is amiss with your unit. A furnace error code can alert you to a specific problem and help you troubleshoot the issue. While all furnaces have different types of codes, most of them follow this standard format. Knowing what each code means and how to respond accordingly can prevent small problems from escalating.